Metal smart card with dual interface capability

ABSTRACT

A dual interface smart card having a metal layer includes an SC module, with contacts and RF capability, mounted on a plug, formed of non RF impeding material, between the top and bottom surfaces of the metal layer. The plug provides support for the IC module and a degree of electrical insulation and isolation from the metal layer. The resultant card can have contact and contactless operating capability and an entirely smooth external metal surface except for the contacts of the IC module.

BACKGROUND OF THE INVENTION

The present invention relates generally to “smart” cards and, moreparticularly, relates to smart cards which have at least one metal layerand are capable of radio frequency transmission (RF) and physicalelectrical interfacing. In particular, the invention relates to dualinterface (i.e., capable of contactless and/or contact operation) smartcards having a metal layer and a rich and aesthetically pleasantappearance.

Smart cards are highly desirable and are in wide use, including: inpayment and ticketing applications, such as mass transit and motorwaytolls; in personal identification and entitlement schemes on regional,national, and international levels; in citizen cards; in drivers'licenses; in patient card schemes; and in biometric passports to enhancesecurity for international travel.

A smart card is a card that includes embedded electronic circuitry suchas an integrated circuit (IC) chip that can be either: (a) a securemicrocontroller, also referred to as a microprocessor, or equivalentintelligence device with internal memory; or (b) a memory chip alone. Asmart card connects or couples to a card reader with direct physicalcontact and/or with a remote contactless radio frequency interface.

There are three general categories of smartcards of interest.

They are referred to herein as (1) contact, (2) contactless and (3) dualinterface, (1) A “contact” smart card includes an IC chip connected to aconductive contact plate on which are mounted a number of physicalcontact pads (typically gold plated) located generally on the topsurface of the card. A contact smart card must be inserted into acontact type smart card reader and transmission of commands, data, andcard status takes place over the physical contact pads, (2) A“contactless” smartcard contains an IC chip and a card antenna by meansof which RF signals are coupled between the smart card's chip and theantenna of a card reader This permits wireless (e.g., RF) communicationbetween the card and a card reader with no direct electrical contactbetween the card and the card reader. A contactless smart card requiresonly close proximity to a reader. Both the reader and the smart cardhave antennae, and the two communicate using radio frequencies (RF) overa contactless link. Most contactless cards also derive power for theinternal chip from electromagnetic signals emitted by the card reader.The range of operation may vary from less than an inch to severalinches. (3) A “dual-interface” smart card has, typically, a single ICchip (but could have two) and includes both contact and contactlessinterfaces. With dual-interface cards, it is possible to access the ICchip(s) using a contact and/or a contactless interface.

It is desirable o make dual interface smart cards which can provide“contactless” and/or “contact” capability. It has also become verydesirable and fashionable to make cards with one or more metal layers. Ametal layer provides a desirable weight and a decorative pattern and/orreflective surface enhancing the card's appearance and aesthetic value.This is especially desirable for use by high-end customers. It istherefore desirable to make dual interface (contacts and contactless)smart cards having a metal layer.

However, several problems arise in the making of dual interface(“contactless” and “contact”) smart cards with a metal layer because ofconflicting requirements. By way of example, to construct a dualinterface smart card, the contact pads associated with the IC chip needto be located along an external surface (top or bottom, but normallytop) of the card to make contact with a contact card reader and the ICchip will generally be located near the top surface. However, any metallayer in the card interferes with radio-frequency (RF) communicationsignals (e.g., attenuates) between the card and the reader, and thiscould render the contactless smart card useless. So, a dual interfacesmart card with a metal layer needs to solve the problem of RFinterference with respect to the IC chip. Compounding the problem is therequirement that the dual interface metal smart card have a highlysophisticated appearance. Due to the prestige and aesthetic aspect ofthese cards it is desirable that there be no perceptible depression orbump along the surface of the card, except for the contact pads.

SUMMARY OF THE INVENTION

A dual interface smart card embodying the invention includes a top metallayer with a non-metallic plug formed within the metal layer to enablethe placement of an IC module about the plug so the card can function ascontact and/or contactless card. At the same time the card is made tohave a relatively smooth and beautiful external surface.

In general, a hole (opening or cut-out) is formed in the plug forlocating an IC chip module about the center area of the plug so the ICmodule is isolated and insulated from the metal layer. Thus, the plugfunctions to provide a physical separation and a degree of electricalinsulation between the chip module and the metal layer in the horizontaland vertical directions. In addition, the hole in the plug provides apathway for RF transmission. The chip module includes contacts whichextend along the same horizontal surface as the metal layer to enablecontact capability with a contact card reader and the chip moduleextends within the plug's hole to enable contactless (RF) operatingcapability.

In a particular embodiment the metal layer is a relatively thick layerhaving a top surface which defines the top surface of the card. A plugis formed in the metal layer below the top surface so the plug is notseen from the top and does not affect the appearance of the card. Thelateral dimensions of the plug are greater than the lateral dimensionsof the chip module to provide insulation and isolation. A hole is formedvertically down through the plug and an underlying ferrite layer to forma passageway for RF signals to pass between a card booster antenna andan IC module chip antenna. The lateral dimensions of the hole plug aresmaller than the lateral dimensions of the IC chip module.

A dual interface smart metal card embodying the invention includes ametal layer in which is disposed an integrated circuit (IC) module toprovide contactless (RF) and contact capability. The metal layer has atop surface and a bottom surface extending generally parallel to eachother. At least two different sized cut outs are formed in the metallayer, one above the other, both cut outs extending in the horizontalplane, symmetrically about the same centerline. One cut out is formed toposition and nestle the IC module within the top surface of the metallayer and to enable the IC module, which has contacts to make to a cardreader. The IC module and its corresponding one cut out have a depth ofapproximately D1, a length L1 and a width W1. The other cut (also calleda “pocket”), underlying the one cut out, extends from the bottom surfaceof the metal layer until a distance D1 from the top surface. The pocketis made to have a length L2 greater than L1 and a width W2 greater thanW1 to enable RF transmission between the IC module and a card reader. Anon-metallic plug designed to fit snugly within the pocket fills thepocket and is attached to the walls of the pocket. The plug has acentrally located opening having a length L3 which is smaller than L1and a width W3 which is less than W1.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be understood more completely from the followingdetailed description of presently preferred, but nonethelessillustrative, embodiments in accordance with the present invention, withreference being had to the accompanying drawings, which are not drawn toscale, but in which like reference characters denote like components;and

FIG. 1 is a simplified, isometric diagram of a smart card 10 with ametal layer 30, embodying the invention;

FIG. 1A is a highly simplified, idealized isometric diagram of anintegrated circuit (IC) module capable of contactless and contactoperation intended for use in making smart cards embodying theinvention;

FIG. 1B is a simplified idealized cross sectional diagram of the ICmodule of FIG. 1A used in the card shown in FIG. 1;

FIG. 2 includes cross sectional diagrams of various processing steps (1through 7) to form a card embodying the invention;

FIG. 3A is a simplified cross sectional diagram of a card being made asshown in step 5 of FIG. 2;

FIG. 3B a top view of a card being formed as shown in FIG. 3A with aplug (34) and the opening (36) formed in the plug;

FIG. 3C is a top view of the top layer of a card embodying the inventionformed in accordance with the process shown in FIG. 2;

FIG. 4 includes cross sectional diagrams of various processing steps (1through 5) to form a card according to another aspect of the invention;

FIG. 5A is a cross sectional diagram corresponding to step 4 of FIG. 4showing a plug and openings formed in the plug prior to insertion of anIC module;

FIG. 5B is a top view of a card having the cross section shown in FIG.5A showing the plug and openings formed in the plug prior to insertionof an IC module formed in accordance with FIG. 4;

FIG. 5C is a top view of a card formed according to the process stepsshown in FIG. 4 and as shown in FIGS. 5A and 5B with an IC moduleinserted in the opening for the module; and

FIG. 6 is a cross-sectional diagram showing a masking layer formed on acard such as the one shown in FIG. 5C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An integrated circuit (IC) module 7 having multiple contacts as shown inFIG. 1A is to be mounted in, and on, a card 10 as shown in FIG. 1 withthe top surface of the IC module and its contacts generally flush withthe top surface of the card. By way of example it is shown that thelength, width and depth of the card may respectively be approximately3.37 inches by 2.125 inches by 0.03 inches. For purpose of illustrationand the discussion to follow assume, as shown in FIG. 1A, that the ICmodule has a depth D1, a length L1 and a width W1. Modules such as ICmodule 7 are commercially available, for example, from Infineon or NXP.The lateral dimensions of some of these modules were approximately 0.052inches by 0.47 inches with a depth ranging from 0.005 inches to morethan 0.025 inches. These dimensions are purely illustrative and ICmodules used to practice the invention may be greater or smaller insize.

As shown in FIG. 1B, IC module 7 contains an internal microprocessorchip 7 a, a chip antenna 7 b and a contact pad 7 c. Pad 7 c may be aconventional multi-contact pad used in contact-type smart cards and ispositioned to engage contacts in a contact card reader (not shown) whenthe smart card is inserted therein. An epoxy blob 7 d encapsulates thebottom side of the IC module. The epoxy blob allows the IC module to beeasily attached (e.g., by gluing) to an underlying surface.

As noted above, the invention is directed to the manufacture of a smartmetal card having dual interface capability and also having a topsurface which is free of any bumps or depressions, except for: (a) theIC module and its contacts, and/or (b) any design or textureintentionally formed on the top surface. In accordance with theinvention, a card can be made to have a highly aesthetic, smooth andvisually pleasing appearance even though the card must include dualinterface capability (i.e., contact and contactless capability). Thatis, smart cards having a metal layer as a top surface, for aestheticreasons, must include an IC module and its associated contacts. For thecard to be used in a contact mode, the contacts of the IC module have tobe located along an exterior surface of the card. Typically, thecontacts are located along the top surface of the card although thecontacts could conceivably be located along the bottom surface of thecard. To enable effective wireless (RF) transmission there has to be acut out (opening) in the metal layer underlying and surrounding the ICmodule. A challenge is to produce these cut outs (openings) in the metallayer without affecting the smooth, aesthetic, exterior (e.g., top)appearance of the card.

A method of forming a card in accordance with the invention includes thestructure and processing steps illustrated in FIG. 2.

-   -   1—A metal layer 30 is selected which is intended to serve as the        top layer of a card 10 (as shown in step 1 of FIG. 2). The metal        layer 30 has a top (front) surface 301 and a bottom (back)        surface 302; the front and back surfaces are generally parallel        to each other. The thickness (D) of the metal layer 30 may range        from less than 0.01 inches to more than 0.02 inches. In one        embodiment the metal layer 30 was made of stainless steel and        its thickness was 0.0155 inches. Metal layer 30 may, by way of        ample and not by way of limitation be selected to be iron,        tantalum, aluminum, brass, copper or any alloy or compound        thereof.    -   2—A pocket 32 is formed along the underside of layer 30. It may        be referred to as a reverse pocket formed starting from the        bottom surface of metal layer 30 (as shown in step 2 of FIG. 2).        The pocket 32 may be formed in any known manner including, but        no limited to: milling, casting, 3D printing, laser cutting,        water jet electro-discharge (EDM). The pocket 32 has a top 321        which ends a distance (or thickness) D1 below top surface 301,        where D1 is typically equal to (or nearly equal to) the depth of        the IC module 7. The depth (thickness) D2 of pocket 32 is then        equal to (D−D1) inches. D2 will generally always be set to equal        the depth D of the metal layer 30 minus the thickness D1 of the        IC module used to form the card. The pocket 32 may be of regular        or irregular shape, a rectangular solid or a cylinder whose        planar projection in the horizontal plane may be a square, a        rectangle or a circle. The lateral dimensions [length (L2) and        width (W2)]of the pocket 32 can be, respectively, equal to or        greater than the lateral dimensions [length L1 and width W1] of        the IC module as further discussed below. In the embodiments L2        and W2 are shown to be, respectively greater than L1 and W1, but        that is not a necessary condition.    -   3—A plug 34 of any material which does not substantially        interfere with RF transmission (e.g., any non-metallic material,        or even a material such as tungsten or a composite thereof) is        formed or shaped to conform to the dimensions of the milled        pocket 32 and is inserted in the pocket to fill the milled (cut        out) region (as shown in step 3 of FIG. 2). As discussed below        the plug functions to electrically isolate and insulate the IC        module from the metal layer and to also physically secure the IC        module. The interior of the pocket 32 and/or the exterior of the        plug 34 is/are coated with a suitable adhesive (e.g., such as        acrylic or acrylic modified polyethylene, cyanoacrylate,        silicone elastomer, epoxy) so the plug 34 adheres firmly to the        walls of the pocket throughout the processing of the metal layer        in the formation of the card. The plug 34 may be made of any        thermoplastic material such as PET, PVC or other polymer or any        material such as curable resin or epoxy or a ceramic or even of        tungsten material which does not significantly impede radio        frequency (RF) transmission.    -   4—As shown in step 4 of FIG. 2, an adhesive layer 42 is used to        attach a ferrite layer 44 to the back surface 302 of layer 30.        The ferrite layer 44 is placed below the metal layer 30 to act        as a shield (reflector) to prevent/reduce metal layer 30 from        interfering with radio frequency radiation to and from the smart        card. Ferrite layer 44 decreases the “shorting” effect of metal        layer 30 for enabling transmission or reception via antenna 47.        Those skilled in the art will appreciate that it would also be        possible to form or lay out the ferrite material in a different        manner.        -   Also, an adhesive layer 46 is used to attach a plastic            (e.g., PVC) layer 48 which contains and/or on which is            mounted a booster antenna 47. Layer 48 may be made of PVC or            polyester and may be between 0.001 and 0.015 inches thick.            The windings of booster antenna 47 may range from less than            80 microns to more than 120 microns in diameter and may be            secured to layer 48 by ultrasonic welding or heating the            wire prior to placing it in contact with the plastic layer            or by any other suitable process. A layer 52 which includes            a signature panel and a magnetic stripe may be attached to            layer 48 before or after lamination. Layers 42, 44, 46, 48            (and possibly 52) may be formed as a sub-assembly 40 and            attached to the bottom side 302 of metal layer 30.    -   5—The assembly comprising layers 30, 42, 44, 46 and 48 is        laminated (as indicated in step 5 of FIG. 2) to form a card        assembly 50.    -   6—A hole (or opening) 36 is then formed (e.g., by milling)        through the metal 30 to a depth D1 from the top surface and,        concurrently, a hole 362 is then formed in plug 34, (e.g., by        drilling about the center of the plug 34) and through the        underlying layers 42, 44 and 46 until layer 48, as shown in step        6 of FIG. 2. The lateral dimensions of hole 36 formed in the        metal layer 30 are designed to correspond to the dimensions L1        and W1 of the IC module 7 so the IC module can be inserted in        the hole (opening) 36. The lateral dimensions of the hole 362        formed in the plug 34 will be L3 and W3, where L3 and W3 are        less than L1 and W1. So made, plug ledges 341 a will provide        support for the IC module and keep it at its designed height of        D1 below the top card surface. The IC module can be snugly        inserted and attached to the sides of opening 36 and to top 341        a of the plug 34. That is, the IC module can be inserted with        tight clearance and glued in place. The smaller hole (opening)        362 formed below hole 36 accommodates the rear (bottom) end of        module 7. Hole 362 extends vertically down through ferrite layer        44 and is made sufficiently wide to enable RF signals to pass        between antenna 47 and the chip antenna 7 b.        -   With respect to the operation of the card, booster antenna            47 is designed to capture radio frequency energy generated            by an associated card reader (not shown) and to communicate            with the card reader. By design, module antenna 7 b is            sufficiently close to couple inductively with antenna 47,            thereby providing signals from antenna 47 to chip 7 a, while            keeping the chip electrically isolated from antenna 47. In            operation, ferrite layer 44 shields metal layer 30, to make            it possible for radio frequency radiation to enter and be            emitted from card 10. In operation, ferrite layer 44 shields            metal layer 30, to make it possible for radio frequency            radiation to enter and be emitted from card 10. Booster            antenna 47 is designed to capture radio frequency energy            generated by an associated card reader (not shown) and to            communicate with the card reader. By design, module antenna            7 b is sufficiently close to couple inductively with antenna            47, thereby providing signals from antenna 47 to chip 7 a,            while keeping the chip electrically isolated from antenna            47.    -   7—As shown in Step 7 of FIG. 2, an IC module 7 which, as shown        in FIG. 1B, includes a chip 7 a, a chip antenna 7 b and a set of        contacts 7 c is positioned within hole 36. The IC module 7 is        glued in place completing the formation of a card embodying the        invention.        -   To appreciate the appearance of the card as finally formed            reference is first made to FIG. 3A (which is essentially a            copy of step 6 of FIG. 2) and to FIG. 3B. FIG. 3B is a top            view of the card being formed showing the openings (36 and            362) formed in the metal and the plug. Note the hole 36 in            metal layer 30 will have edge(s) 361 and the hole 362 in the            plug and the underlying layers 42, 44, 46 will have edge(s)            345/367. The portion of the plug 34 below region 341 b and            the outer edge 343 of the plug will not be seen, Hence outer            edge 343 is shown with dashed lines.        -   The resultant FIG. 3C is a top view of a card 10 showing the            module 7 mounted and inserted in the top of the card. The            plug 34 is not seen since it is underneath the metal layer.            Thus, the top surface of a card 10 formed in accordance with            the process steps shown in FIG. 2 displays a completely            smooth unbroken metal surface (except for the contact pad of            the IC module). The underlying plug is covered (hidden) by            an overlying metal region. Significantly, the card having            the desired beautiful physical appearance can function as a            wireless (contactless) card or as a contact card.

The dimensional tolerances of the various holes/openings and of thecomponents need to be close enough so that on a platen lamination allparts fuse together with no airspace or sinks in the outward appearanceof the card.

As shown in the Figures, metal layer 30 has a cut out 36 formed in itstop surface. The thickness/depth D1 of cut out 36 is made substantiallyequal to the depth of the IC module 7. The hole/opening 36 is machinedthrough metal layer 30 dimensioned to receive module 7, which is securedtherein, as by bonding. Module 7 contains a microprocessor chip 7 a(internally), a chip antenna 7 b and a contact pad 7 c. Pad 7 c is aconventional contact pad used in contact-type smart cards and ispositioned to engage contacts in a card reader when the smartcard isinserted therein.

By design, plug 34 is substantially wider than module 7. Preferably,plug 34 extends at least 0.04 laterally beyond either side of module 7.This prevents the metal in substrate 30 from interfering withcommunication between the card and chip. However, the plug does not haveto be wider than module 7 (i.e., its lateral dimensions need not begreater than those of the module).

Module 7 is positioned vertically within metal layer 30 so as to providea contact pad 7 c along the top metal surface to realize the contactfunctions of the dual interface. Moreover, positioning module 7 on plug34 which is made larger (though not necessarily so) in area than themodule 7 makes it possible to decrease interference in the radiocommunication between module antenna 7 b and the booster antenna 47.

Although preferred embodiments of the invention have been disclosed forillustrative purposes, those skilled in the art will appreciate thatmany additions, modifications, and substitutions are possible withoutdeparting from the scope and spirit of the invention,

Alternatively, cards embodying the invention may be formed as shown inFIGS. 4, 4A, 5A, 5B, 5C and 8. These cards differ from those discussedabove in that a plug is formed whose thickness is equal to the thicknessof the metal layer. That is, there is no recessed pocket.

As shown in FIG. 4, a card formed in accordance with this aspect of theinvention may include the following processing steps and structure:

-   -   1—A metal layer 30 is selected (as shown in step 1 of FIG. 4)        which is intended to serve as the top layer of a card 10. The        metal layer 30 has a top (front) surface 301 and a bottom (back)        surface 302 and a thickness (D) which may range from less than        0.01 inches to more than 0.02 inches. Metal layer 30 may have        the same characteristics and properties as metal layer 30 shown        and discussed above.    -   2—A hole 420 of depth D is formed in the metal layer 30 (as        shown in step 1 of FIG. 4). The lateral dimensions of the hole        are L2 and W2 (see FIGS. 5A and 5B). The hole 420 may be formed        in any known manner (e.g., casting or milling). The hole 420 may        be a regular or irregular solid cube, or a cylinder whose planar        projection in the horizontal plane may be a square, a rectangle        or a circle or an irregular shape. In the embodiment shown in        FIG. 4, the lateral dimensions [length (L2) and width (W2)] of        the hole 420 are respectively greater than the lateral        dimensions [length L1 and width W1] of the IC module as further        discussed below. Generally, L2 is greater than L1 (by at least        0.04 inches and W2 is greater than W1 (by at least 0.04 inches).        However, as noted above, L2 may be made equal to L1, and W2 may        be made equal to W1. The advantage of making L2 and W2,        respectively, larger than L1 and W1 is to provide greater        separation between the metal layer and the IC module and thus        enhance RF transmission and reception.    -   3—A plug 434 of any material like plug 34 which does not        interfere with RF transmission is formed or shaped to conform to        the dimensions of the hole 420 to fill the cut out region (as        shown in step 2 of FIG. 4). Plug 434 is processed and functions        to secure the IC module. The interior walls of the hole 420        and/or the exterior walls of the plug 434 is/are coated with a        suitable adhesive so the plug 434 adheres firmly to the walls of        the hole throughout the processing of the metal layer in the        formation of the card. The plug 434 may be made of any        thermoplastic material such as PET, PVC or other polymer or any        material such as epoxy resins and a ceramic.    -   4—As shown in step 3 of FIG. 4, an adhesive layer 42 is used to        attach a ferrite layer 44 to the back surface 302 of layer 30.        An adhesive layer 46 is used to attach a plastic (e.g., PVC)        layer 48 which contains and/or on which is mounted a booster        antenna 47 to the ferrite layer. Layers 42, 44, 46, and 48 and        the booster antenna 47 are formed in a similar manner as the        corresponding number components shown in FIG. 2 and serve the        same or similar functions.    -   5—The assembly comprising layers 30, 42, 44, 46 and 48 is        laminated to form a card assembly 350 (as indicated in step 3 of        FIG. 4).    -   6—A T-shaped hole/opening 436 is then formed through the plug        434. The hole 436 is formed by milling, drilling and/or any        other suitable means. The top portion 436 a of T-shaped hole 436        is formed to have lateral and depth dimensions to accommodate        the IC module. Where the dimensions of IC module 7 are L1 by W1        by D1 the top portion of 436 a will be formed to be just about        L1 by W1 by D1 to enable the IC module to be snugly inserted        within the hole 436 a and to be glued in place. The bottom        portion 436 b of the hole 436 formed in plug 434, (by drilling        vertically down about the center of the plug 434) extends        through the underlying layers 42, 44 and 46 and until layer 48,        as shown in step 4 of FIG. 4. The lateral dimensions of hole 436        b formed in plug 434 are made large enough to enable sufficient        RF signals to pass between booster antenna 47 and the IC chip        module 7 to enable RF communication to take place reliably. The        lateral dimensions of the hole 436 b formed in the plug 434 are        denoted as L3 and W3, where L3 and W3 are less than L1 and W1.        Note that making L3 and W3 less than L1, and W1, respectively,        results in the formation of ledges 438 which will provide        support for the IC module and keep it at its designed height of        D1 below the top card surface 301. The IC module 7 can be snugly        inserted and attached (glued) to the ledges 438 and the top        interior walls of the plug 434.    -   7—As shown in Step 5 of FIG. 4, IC module 7 which includes a        chip 7 a and a chip antenna 7 b and a set of contacts 7 c is        positioned within hole 436 a is glued in place.

FIG. 5A is an enlarged cross sectional diagram corresponding to step 4of FIG. 4. FIG. 5B is a top view of a card showing the holes formed inthe metal and the plug. FIG. 5C is a top view of a card showing themodule 7 mounted and inserted in the top of the card. The smart metalcard 10 can function as a wireless (contactless) card or as a contactcard. Note that as shown in FIGS. 5A, 5B and 5C the hole portion 436 ahas an inner edge 410. The plug has an outer edge 442. As is evidentfrom FIGS. 5B and 5C, the IC module 7 will cover openings 436 a and 436b. As a result there is a space/area 450 between edges 440 and 442extending around the outer periphery of the IC module between the module7 and the metal layer 30. The space/area 450 may be objected to onaesthetic grounds as it detracts from the continuous metal layer (exceptfor the necessary module contact pad). However, it should be appreciatedthat the space area 450 may enhance RF transmission. The presence ofspace/area 450 and an depression or bump related to space 450 may bemasked by the addition of a masking layer 470, as shown in FIG. 6. Thismay be acceptable in many instances. However, in instances where such asolution is still not acceptable or feasible, the solution is to revertto making cards as per the process steps shown in FIG. 2.

Thus, a problem with the smart cards formed in accordance with theprocess shown in FIG. 4 is that a portion of a plug may be seen. Theportion of the plug may mar the continuous appearance of the card and/oras a bump on the surface or as a depression. This may be so, even if amasking (concealing) layer 470 is formed over layer 30.

As taught and discussed with reference to FIG. 2, above, the spacing andany discontinuity in the metal surface (except for the IC module) areavoided by forming a recess pocket 32 in substrate 30 and filling therecess with a plug 34 which is not seen from the top of the card. Thus,in contrast to previous and other dual interface smart metal cards, theplug 34 does not appear as a bump on the surface or as a depression. Itis not visible when the card is viewed from the outside. The process ofFIG. 2 thus differs from the process of FIG. 4 where a through hole 420is formed in the metal layer 30 and a plug 434 is formed which fills thehole 420.

However, it should be noted that in all the embodiments shown herein aplug is used to separate an IC module from a surrounding metal layer topromote RF transmission capability and the plug is also used to positionand secure the IC module within the card. Openings for the plug and itspositioning within the card are designed to maintain the exterior of thecard flat and visually pleasant.

1-22. (canceled)
 23. A card having a card length, a card width, and acard thickness, the card comprising: a metal layer having a top surfaceand a bottom surface extending parallel to each other; an opening insaid metal layer (a) extending from said top surface to said bottomsurface or (b) defined by a first region cut out region in said topsurface of said metal layer and a second cut out region extending fromsaid bottom surface of said metal layer and extending vertically belowthe first cut out region and generally in a symmetrical manner withrespect to the first cut out region; an integrated circuit (IC) modulehaving a depth D1, a length L1 and a width W1 disposed within theopening or the first cut out region, the IC module having contactspositioned along the top surface of the metal layer and configured tocommunicate using RF transmission to enable contactless operation; aplug formed of non-RF-impeding material disposed within said opening orsaid second cut out region, the plug, having lateral dimensions of L2,which is equal to or greater than L1, and W2, which is equal to orgreater than W1; a ferrite layer disposed below the metal layer; avertical hole formed in the plug and through the ferrite layer, thevertical hole having lateral dimensions L3 and W3, which lateraldimensions are less than the respective lateral dimensions L1 and W1.24. The card of claim 23, wherein the first cut out region has a depth,a length, and a width substantially equal to D1, L1, and W1,respectively, with the IC module disposed within the first cut outregion, the second cut out region having dimensions L2 and W2 that aregreater than L1 and W1, respectively, extending vertically until adistance D1 from the top surface, with the plug disposed within thesecond cut out region.
 25. The card of claim 23, wherein said metallayer has a thickness D greater than D1, and the opening in said metallayer extends for a full thickness of said metal layer in which islocated said IC module mounted on said plug, said IC module and saidplug extending between the top and bottom surfaces of the metal layer.26. The card of claim 25, wherein the opening in the metal layer haslateral dimensions of L2 and W2 respectively greater than L1 and W1, theplug is attached to the metal layer and fills the opening within themetal layer, and wherein the plug has a first cut out region withlateral dimensions of L1 and D1 extending for a depth D1 below the topsurface for accommodating the IC module, and a second region below thefirst region which extends until the bottom surface of the metal layerfor a depth of (D−D1).
 27. The card of claim 26, further comprising amasking layer disposed over the top metal surface and any exposedportion of the plug.
 28. The card of claim 23, wherein said metal layercomprises one of stainless steel, iron, tantalum, aluminum, brass,copper, or an alloy or compound thereof, and wherein said plug comprisesa non-metallic substance or a metal that does not impede RFtransmission.
 29. The card of claim 23, wherein the metal layer has alength and width that extend for the full length and width of the card.30. The card of claim 23, further comprising a booster antenna attachedto the ferrite layer for enhancing RF transmission with the IC module.31. The card of claim 30, wherein the booster antenna is configured toinductively couple to the IC module.
 32. A method of making the card ofclaim 23, the method comprising the steps of: selecting the metal layer;cutting out the second cut out region in said metal layer starting fromsaid bottom surface of said metal layer for a distance D−D1 from thebottom surface of said metal layer; securely attaching the plug withinsaid second cut out region, said plug designed to fit in and fill thesecond cut out region; cutting out the first cut out region in said topsurface of said metal layer overlying said second cut out region, saidfirst cut out region disposed symmetrically with respect to the secondcut out region, said first cut out region having a depth D1 and a lengthL1 and a width W1; inserting and securely attaching said IC modulewithin said first cut out region with the contacts of the IC modulepositioned along the same horizontal plane as the top surface of themetal layer; attaching the ferrite layer to the bottom surface of themetal layer; and forming the vertical hole in the plug and said ferritelayer.
 33. The method of claim 32, further comprising including a layerincluding a booster antenna and attaching said booster antenna layer tothe ferrite layer.
 34. The method of claim 33, further comprisinglaminating the metal layer, the ferrite layer and the booster antennalayer.
 35. The method of 33, further comprising attaching a signaturepanel and a magnetic stripe layer to the booster antenna layer.
 36. Amethod for making the card of claim 26, the method comprising the stepsof: selecting the metal layer; forming the opening; securely attachingthe plug within said opening; and inserting said IC module within andsecurely attaching said IC module within said plug first cut out region;attaching the ferrite layer to the bottom surface of the metal layer;and forming the vertical hole in the plug and said ferrite layer. 37.The method of claim 36, further comprising forming a masking layerformed over the top metal surface and any exposed portion of the plug.38. The method of claim 36, further comprising including a layerincluding a booster antenna and attaching said booster antenna layer tothe ferrite layer
 39. The method of claim 38, further comprisinglaminating the metal layer, the ferrite layer and the booster antennalayer.
 40. The method of 37, further comprising attaching a signaturepanel and a magnetic stripe layer to the booster antenna layer.
 41. Ametal smart card with dual interface capability comprising; metal layerof thickness D having a top surface and a bottom surface extendingparallel to each other, the top surface defining, a horizontal plane; anintegrated circuit (IC) module having a top region with contactsconfigured for physical contact with a card reader, said IC module alsoconfigured for contactless radio frequency (RF) communication with acard reader, said IC module having a length L1, a width W1 and athickness D1, wherein D1 is less than D; a plug of non RF impedingmaterial having lateral dimensions of L2, which is equal to or greaterthan L1, and W2, which is equal to or greater than W1; an opening insaid metal layer extending for a full thickness of said metal layer,said IC module mounted on said plug disposed in said opening, said ICmodule and said plug extending in the vertical direction between the topand bottom surfaces of the metal layer, with the contacts of the ICmodule positioned along the same horizontal plane as the top surface ofthe metal layer, the opening in the metal layer having a first region atand just below the top surface for accommodating the IC module and asecond region below the first region which extends until the bottomsurface of the metal layer, the opening in the first region havinglateral dimensions L1 and W1 for a depth of D1 and the second regionhaving lateral dimensions L2 and W2 for a depth of (D−D1), wherein theIC module fits in and fills the opening in the first region and the plugfits in and fills the opening in the second region, wherein L2 and W2are respectively greater than L1 and W1; and a masking layer disposedover the top metal surface and any exposed portion of the plug.
 42. Acard comprising: a metal layer having a top surface and a bottom surfaceextending parallel to each other; a first region cut out in said topsurface of said metal layer, said first region having a depth D1, alength L1 and a width W1; an integrated circuit (IC) module snuglysecured within the first cut out region, said IC module having contactspositioned along the top surface of the metal layer and configured tocommunicate using RF transmission to enable contactless operation; asecond cut out region extending from said bottom surface of said metallayer until a distance D1 from the top surface, said second cut outregion extending vertically below the first cut out region and generallyin a symmetrical manner with respect to the first cut out region; saidsecond cut out region having a length L2 greater than L1 and a width W2greater than W1; and a plug formed of non RF impeding material snuglysecured within said second cutout region.